1. Technical Field
The present invention relates to an intermediate transferer and an image forming apparatus preferably used for electrophotographic image forming apparatuses such as copiers, printers and facsimiles.
2. Description of the Related Art
The intermediate transfer belt used as an intermediate transferer in the electrophotographic image forming apparatus is desired to have: uniformity of electric resistance; surface smoothness; mechanical properties such as high flexibility, high elasticity and high elongatability; high dimensional accuracy such as thickness and circumference.
The intermediate transfer belt is one of expensive components in the electrophotographic image forming apparatus, and is strongly recommended to reduce its cost. An extruded or inflated thermoplastic resin can prepare the intermediate transfer belt at low cost.
However, the intermediate transfer belt formed of the thermoplastic resin has a problem of poor detection of a toner with a toner concentration sensor when initially having high glossiness.
Japanese Patent No. JP-3295745-B1 (Japanese published unexamined application No. JP-H07-113029-A) discloses a polyvinylidene fluoride resin and/or a semiconductive resin composition formed of a fluorine rubber, carbon black and a polyalkylene ether copolymer. This specifies an amount of the carbon black, an amount of the polyalkylene ether and a range of the volume resistivity, but does not disclose anything about the glossiness, surfaceness and appearance. The polyvinylidene fluoride resin may be a homopolymer or a copolymer, but a combination ratio thereof is not disclosed at all.
The electroconductive resin composition formed of the thermoplastic resin tends to deteriorate in glossiness. This is because the resin has a small refractive index, and the carbon black as a conductive agent and an electroconductive resin as an additive enlarge the surface roughness in molding. The electroconductive resin composition tends to cause disfigurement, and when used as an intermediate transfer bell in the electrophotographic image forming apparatus, it has a small difference in refractive index with a toner and the toner is optically difficult to be detected with a toner concentration sensor.